"Could not autowire. No beans of type... found" with Simple project

A couple of possibilities here.

You need to add the @EnableJpaRepositories(basePackages = {"your.pkg.here"}) to the TestApplication. This tells Spring Data to look for your repository classes under the specified package. If the repository package name is the same as the TestApplication, you can skip the basePackages part.

Similarly, if your TestApplication and SimpRepository are not in the same package, you need to add a @ComponentScan with the list of all relevant packages.

I missed a simple @Component for the class. This could be one basic problem.